refactor(shortcuts): use event.code for raw keyboard handlers

Change e.key to e.code in global keyboard shortcut handlers for
consistency with the new event.code-based shortcut system:
- ProjectList.vue: 'j'/'k'/'Enter' -> 'KeyJ'/'KeyK'/'Enter'
- useGanttBar.ts: 'ArrowLeft'/'ArrowRight' (identical values, for consistency)
- Modal.vue: 'Escape' (identical value, for consistency)

frontend/src/components/misc/Modal.vue

@@ -101,7 +101,7 @@ watchEffect(() => {
 })
 
 function onKeydown(e: KeyboardEvent) {
-	if (e.key === 'Escape') {
+	if (e.code === 'Escape') {
 		if (e.isComposing) {
 			return
 		}

frontend/src/components/project/views/ProjectList.vue

@@ -322,13 +322,13 @@ function handleListNavigation(e: KeyboardEvent) {
 		return
 	}
 
-	if (e.key === 'j') {
+	if (e.code === 'KeyJ') {
 		e.preventDefault()
 		focusTask(Math.min(focusedIndex.value + 1, tasks.value.length - 1))
 		return
 	}
 
-	if (e.key === 'k') {
+	if (e.code === 'KeyK') {
 		e.preventDefault()
 		if (focusedIndex.value === -1) {
 			focusTask(tasks.value.length - 1)
@@ -345,7 +345,7 @@ function handleListNavigation(e: KeyboardEvent) {
 		return
 	}
 
-	if (e.key === 'Enter') {
+	if (e.code === 'Enter') {
 		if (e.isComposing) {
 			return
 		}

frontend/src/composables/useGanttBar.ts

@@ -64,31 +64,31 @@ export function useGanttBar(options: UseGanttBarOptions) {
 	function onKeyDown(e: KeyboardEvent) {
 		// task expanding
 		if (e.shiftKey) {
-			if (e.key === 'ArrowLeft') {
+			if (e.code === 'ArrowLeft') {
 				e.preventDefault()
 				changeSize('left', 1)
 			}
-			if (e.key === 'ArrowRight') {
+			if (e.code === 'ArrowRight') {
 				e.preventDefault()
 				changeSize('right', 1)
 			}
 		}
 		// task shrinking
 		else if (e.ctrlKey) {
-			if (e.key === 'ArrowLeft') {
+			if (e.code === 'ArrowLeft') {
 				e.preventDefault()
 				changeSize('left', -1)
 			}
-			if (e.key === 'ArrowRight') {
+			if (e.code === 'ArrowRight') {
 				e.preventDefault()
 				changeSize('right', -1)
 			}
 		}
 		// task movement
-		else if (e.key === 'ArrowLeft' || e.key === 'ArrowRight') {
+		else if (e.code === 'ArrowLeft' || e.code === 'ArrowRight') {
 			e.preventDefault()
 
-			const dir = e.key === 'ArrowRight' ? 1 : -1
+			const dir = e.code === 'ArrowRight' ? 1 : -1
 			const newStart = new Date(options.model.start)
 			newStart.setDate(newStart.getDate() + dir)
 			const newEnd = new Date(options.model.end)